Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already flag destructiveHint=true and idempotentHint=true, but the description adds the crucial PATCH semantic ('only the fields you pass change') and warns that supplied values overwrite stored ones. It does not mention how to clear a field, permission requirements, or the response body, so it is good but not exhaustive.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two compact clauses; the WRITE marker and partial-update rule are front-loaded, and the endpoint path is appended where it is easy to skim. No filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 16-parameter mutation with no output schema, the description covers the highest-risk ambiguity (partial vs full replacement) and defers field-level detail to a fully documented schema. Missing are auth/prerequisite notes and whether custom_attributes are replaced wholesale, but nothing that would cause a wrong call.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and every one of the 16 parameters is documented there, including the empty-string-clears behavior and enum-style gender codes. The description adds no parameter-level detail beyond the general 'fields you pass change' rule, so baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Starts with an explicit WRITE marker, names the specific verb and resource ('change an existing client'), and pins the exact endpoint (PATCH /v3/clients/{id}). This separates it cleanly from agendapro_create_client and agendapro_get_client in the sibling list.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The word 'existing' plus 'partial update' tells an agent this is the modify path, not the create path, and that omitted fields are left alone. It stops short of naming the alternatives (create_client vs update_client) or stating prerequisites such as needing a valid client_id first.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.